Take a white board about 40"x20". Place a 12"Hx8"W black rectangle about 2/3 of the way down the target. Your point of aim is the bottom edge of the rectangle. Now draw a vertical line from the top of the black rectangle. Mark a spot 6.5" up for M91/30, 7.5 inches up for carbines. This is your Control Point. Now, run the target out to 109 yards and make sure the black rectangle is eye level to the shooter. When you get back, place your rear sight on 3. You should fire from a rest, and in the prone when possible. Fire four rounds. If your shot group is no more than 2 inches from the Control Point, and can be covered by a 6 inch disk, you are combat zeroed.